Absence of evidence is not evidence of absence

Burden of proof.

Absence of evidence is not evidence of absence.

True. But neither is it an argument in favor of existence.

The Wolf

If I first demonstrate that it is the regular practice of airlines to record the names of every individual flying on a given flight, I can then prove I did not take the flight because there is no record with the airline of me on the flight. In other words, the absence of evidence of me being on the flight becomes evidence of my absence from the flight.

One could argue that’s evidence of absence from the outset, not absence of evidence.

Your title an excellent statement! I used it for the first time today, thanks to you putting it up here 🙂

Catch yourself: A catchy quote is an oversimplification and completely misses what evidence is supposed to be ie support a claim. Absence of evidence isnt evidence against is only because there may be other evidence. Certainly if you’ve ruled all possible evidence out, that is evidence against whatever was trying to be supported. The less evidence there is, the less reason to believe it, and as you rule out possible evidence, the less likely there will be reason to believe it. With is evidence against, as it moved you in another direction, even though at some point it is possible to swing the other way. Reiyah is a proof if I’m not mistaken.

k-cup and Non Political,

You are confusing evidence and burden of proof. The absence of evidence not being evidence of absence (without other evidence demonstrating why evidence ought to be expected in this circumstance) is self-evidently true logical axiom. It doesn’t matter if there is or is not other evidence. That doesn’t mean claims for which there is no evidence are true. It simply means that there is no evidence in which to make a determination either way (in real life there are very few claims for which there is no evidence for or against). But the burden of proof will be on the person making the claim. So you can claim that everything is made out of invisible unicorns but the burden of proof (to the extent anyone cared to ask) would be on you. To sustain your burden, you would have to present some evidence.

No faith or belief in the world has lasting power without evidence. We may also have evidence against their claims, the evidence may be fabricated, or we may dismiss their claims because prior assumptions, but the claims themselves will have evidence to support them.

I am not confusing it with burden of proof. Absence of evidence can be actual evidence if whatever you are claiming calls for a specific result and the result doesn’t come through. That would be evidence that the claim is incorrect. That is not burden of proof.

beninguiman
“The absence of evidence not being evidence of absence (without other evidence demonstrating why evidence ought to be expected in this circumstance) is self-evidently true logical axiom.”

I’m confused you had it right the first time with your excellent airplane example.
Though you dont need to be that complicated.
The classic example is if I say there is an elephant in the room (a literal elephant). You can quickly look around not see it and prove me wrong. Thus absence of evidence is in fact evidence of absence. However if say there is a flea in the room. Your not seeing it is not evidence of is absence.
Arguably the elephant being a large visible animal that cant hide in this small room is “other evidence demonstrating why evidence ought to be expected in this circumstance” but tht is often the case.

@benignuman
“No faith or belief in the world has lasting power without evidence. We may also have evidence against their claims, the evidence may be fabricated, or we may dismiss their claims because prior assumptions, but the claims themselves will have evidence to support them.”

Really? Then you know something about christanity that the catholic church doesn’t. The hold that to believe the ikrai emmuna of their theology requires a leap of faith and is not evidence based. There staying power hasn’t suffered much due to the lack of evidence.

Catch yourself, the absence of evidence to support the claim of gravity is evidence that there is no gravity even though no evidence was brought to discredit the theory of gravity.
Here is how people use the phrase “lack of evidence …”,
Lack of evidence for theory A doesn’t mean it’s been discredited (not no evidence is not the same thing as evidence)
However If I claim A because of observation B (usually how theory are born), and B doesn’t really happen, I do not need to evidence against your claim A, because you’ve given an expectation of B. Often, there isn’t an expectation of B. If I come along and say C is inconsistent, that’s evidence against.
Bemigman, read my first post, that is what I wrote above. It wasn’t clear because the second was a follow up.

“My point is that absence of evidence as evidence of absence will (logically) always require additional information”
I understand hy yo uused the airplane example. My point is even without that the reality is that often the absence of evidene IS evidence of absence. granted this depends on the statment in question and preexisting knowledge (evidence) regarding what I am trying to convice you

but the reality is that there is always more information required for any stament to have meaning.

If I want to convince you there is a flea in the room, in order for that statment to have any meaning you have to know what a flea is. Ditto for an elephant it isnt a special case.
The key question is whether evidence should exist but does not. “Absence of evidence is not evidence of absence.” is only true if you wouldnt necessarily expect evidence of its existence, like seeing a flea. If you would expect evidence of its existence liek seeing an elephant then absence of evidene is in fact evidence of absence.
thus your stament “The absence of evidence not being evidence of absence (without other evidence demonstrating why evidence ought to be expected in this circumstance) is self-evidently true logical axiom. ” while true, is quite limited

I dont think we are arguing. I am just poitning out that your caveat “always require additional information, i.e. evidence of why we should expect to see the evidence that we do not see.”
I s present so often that the rule “Absence of evidence is not evidence of absence” isn’t much of a rule at all.